option-O override when search bar is shown in editor

I use umlaut keys with a ascii keyboard layout, so to type eg ø I use option-O, option-A for å, etc (am on a mac). This works in the editor, but when the search bar is shown, eg after pressing command-F, option-O now moves to the next found instance of the current search string. 

I haven't found a way to turn this off, since searching for this shortcut in the preferences doesn't yield any results. Is there a way to fix this?